Outboard axle bearing structure for a bicycle or motorcycle

ABSTRACT

In one example, a structure for attaching a wheel to one of a frame of a motorcycle or a bicycle may include an axle having first and second opposing end portions and supporting a wheel, a left axle support collar structure configured to support the first opposing end portion of the axle, and a right axle support collar structure configured to support the second opposing end portion of the axle. A first bearing is positioned in the left axle support collar structure, and a second bearing is positioned in the left axle support collar structure. The axle rotates relative to the frame.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 15/069,526(published as U.S. Publication No. US 2016-0194050-A1), entitled“Outboard Axle Bearing Structure for a Bicycle or Motorcycle,” and filedon Mar. 14, 2016 which is a continuation of U.S. Pat. No. 9,283,809,entitled “Outboard Axle Bearing Structure for a Bicycle or Motorcycle,”and filed on Apr. 23, 2012 which is a continuation of U.S. Pat. No.8,162,344, entitled “Outboard Axle Bearing Structure for a Bicycle orMotorcycle,” and filed on Jul. 2, 2008, which claims under 35 U.S.C. §119(e) the benefit of both U.S. Patent Application No. 60/947,824 andentitled “Outboard Axle Bearing System for a Bicycle or Motorcycle,”filed Jul. 3, 2007, and U.S. Patent Application No. 60/947,898 andentitled “Single Sided Chain Stay Structure for a Bicycle,” filed Jul.3, 2007, both of which are assigned to the Assignee of this application.The contents of each of the foregoing applications are herebyincorporated by reference in their entireties as if fully set forthherein.

FIELD OF THE INVENTION

The invention is a hub system for attaching a wheel to a bicycle, andmore particularly a hub system where the bearing is mounted on the frameand the axle rotates relative to the frame.

BACKGROUND OF THE INVENTION

Currently, wheel hubs for bicycles have internal axle bearings. Thesebearings allow the wheel to rotate with respect to the axle and frame.In these current designs the axle is fixed rigidly to the frame or forkand it does not rotate respectively thereto. Hub designs, especiallyrear hubs, have constraints on them due to componentry that areinstalled on the hub; such as gear cassettes and disc rotors for discbrake assemblies. These constraints are related to, but not limited to,bearing size, axle size and load capacity.

There is needed in the art an axle and hub design wherein these designconstraints are addressed.

SUMMARY OF INVENTION

The invention described herein pertains to the mounting of a wheel on amotorcycle, bicycle or other such vehicle, where the bearings forsupporting the axle of the wheel are mounted to the frame as opposed tothe wheel structure itself. Thus, in one aspect this invention may allowthe axle to rotate relative to the frame.

One example of the invention may take the form of a structure forattaching a wheel to a frame of a bicycle. The structure may include anaxle having first and second opposing end portions and supporting awheel, a left axle support collar structure configured to support thefirst opposing end portion of the axle, and a right axle support collarstructure configured to support the second opposing end portion of theaxle. A first bearing may be positioned in the left axle support collarstructure, and a second bearing may be positioned in the left axlesupport collar structure. The first and second bearings may allow theaxle to rotate relative to the frame.

Further to this example, the left axle support collar structure mayinclude a chain stay axle support collar and a seat stay axle supportcollar. In another example, the first bearing may be positioned in thechain stay axle support collar and the second bearing may be positionedin the seat stay axle support collar. In a further example, the firstbearing may include at least one inner race configured to engage theaxle and a first outer race associated with the left seat stay supportcollar and configured to rotate relative to the at least one inner race.In another example, the second bearing may include a second outer raceassociated with the left seat chain stay support collar and separatefrom the first outer race, and the second outer race may be configuredto rotate relative to the at least one inner race. In a further example,the at least one inner race includes a common inner race and the firstouter race and the second outer race may both be configured to rotaterelative to the common inner race.

In another example, the left axle support collar structure may include afirst chain stay axle support collar and a first seat stay axle supportcollar. The right axle support collar structure may include a secondchain stay axle support collar and a second seat stay axle supportcollar, and a bearing may be positioned in each of the first and secondseat stay axle support collars and the first and second chain stay axlesupport collars. In a further example, the wheel may include a hub, thehub may be received on the axle, and the axle and the hub may rotatetogether. In another example, the hub may be removable from the axle. Ina further example, the hub may have opposing ends, with each of theopposing ends forming a threaded recess. The hub may be positionedbetween the left axle support collar structure and the right axlesupport collar structure. In this example, a first retaining fastenermay be received through the first and second bearings in the left axlesupport collar structure and received in one threaded recess in the hub,and a second retaining fastener may be received through the right axlesupport collar structure and received in the other threaded recess inthe hub. In other examples, a third bearing may be positioned in theright axle support collar structure, and a fourth bearing may bepositioned in the right axle support collar structure.

Another example of the invention may take the form of a bicycle forriding on a support surface. The bicycle may include a frame, at leastone wheel for engaging a support surface and including an axle withopposing first and second end portions, and a first axle supportstructure configured to support the first end portion of the axle. Thefirst axle support structure may include a first axle support collar, asecond axle support collar, a first bearing positioned in the first axlesupport collar, and a second bearing positioned in the second axlesupport collar.

In another example, the bicycle may include a second axle supportstructure configured to support the second end portion of the axle. Thesecond axle support structure may include a third axle support collarand a third bearing positioned in the third axle support collar. Theaxle may rotate in the first, second, and third bearings relative to theframe. In another example, the second axle support structure may furtherinclude a fourth axle support collar and a fourth bearing positioned inthe fourth axle support collar. The axle may rotate in the first,second, third, and fourth bearings relative to the frame.

Another example of the invention may take the form of a structure forattaching a wheel to a frame of a bicycle. The structure may include anaxle having opposing end portions and supporting a wheel, and a leftaxle support collar structure configured to support one of the opposingend portions of the axle. The left axle support collar structure mayinclude a separate chain stay axle support collar and a separate seatstay axle support collar, and a first bearing structure positioned inthe left axle support collar structure. The first bearing structure mayinclude at least one first ball bearing positioned between the chainstay axle support collar and the axle. The at least one first ballbearing may allow for rotation of the axle relative to the chain stayaxle support collar. The first bearing structure may further includeleast one second ball bearing positioned between the seat stay axlesupport collar and the axle. The at least one second ball bearing mayallow for rotation of the axle relative to the seat stay axle supportcollar.

In some examples, the axle may include an axle body and at least oneaxle extension. The first ball bearing may be positioned between thechain stay axle support collar and the at least one axle extension, andthe second ball bearing may be positioned between the seat stay axlesupport collar and the at least one axle extension.

Further non-limiting benefits and features of the invention describedherein are observed by the disclosure of the detailed specification,drawings, and claims provided herein.

FIGURE DESCRIPTION

FIG. 1 shows a bicycle incorporating at least one aspect of the currentinvention.

FIG. 2 shows a portion of a rear triangle where the seat stay and chainstay structures are of unitary construction.

FIG. 3 shows a portion of a rear triangle where the seat stay and chainstay structures are not of unitary construction.

FIG. 4 is a section taken along line 4-4 of FIG. 1 where the chain stayand seat stay are of unitary construction as shown in FIG. 2.

FIG. 5 is a section taken along line 5-5 of FIG. 1 where the chain stayand seat stay are of non-unitary construction.

FIG. 6 is a representative cross section of a tapered bearing usable fora structure such as that shown in FIG. 4.

DETAILED DESCRIPTION

The invention described herein relates to the placement of thebearing(s) relative to a wheel hub for use on a bicycle or motorcycle,or other such vehicles where a wheel is rotatably connected to afork-like structure. As described herein, reference is made to a bicyclestructure for clarity purposes, but does not limit the applicability toother types of vehicles and related structures this invention may applyto.

As an introduction, in a typical hub design for connecting a wheel to afork structure, the bearings are internal to the hub structure. In thesetypical designs, the axle is fixed to the frame, such as at a forkstructure (which is hereby defined to include front forks and reartriangle wheel mounting and connection structures), and does not rotaterelative thereto. The hub, often including the gear cassette, disc brakerotor, and spoke anchors, is received on the fixed axle, and rotatesrelative to the fixed axle by way of at least one bearing positionedbetween the hub and the fixed axle.

The instant invention encompasses a structure and associated method thatallows the axle to rotate relative to the fork structure (and thus theframe) by repositioning the bearings from inside the hub and engagingthe axle to being set in the forks and rotatably receiving the axle. Thehub may then be integral with the axle, or may be a separate structurefrom the axle, but in any event may rotate in conjunction with the axle.The invention(s) encompassed herein are further described below withreference to the figures and set forth in the claims.

FIG. 1 shows a bicycle 20 encompassing the present invention. Thebicycle includes a common frame structure 22 having a top tube 24 anddown tube 26 and seat tube 28. The top tube and down tube are connectedat a front end to a head tube 30. The head tube supports a front fork32, wheel 34 and handlebar 36 in movable engagement with the frame 22.The rear end of the top tube engages the top end of the seat tube 28. Aseat post 37, supporting a seat 38, is adjustably inserted into the topend of the seat tube. The rear end of the down tube engages the bottomend of the seat tube at or near a bottom bracket 40. The bottom bracketrotatably supports the crank set 42. The crank set includes cranks 44and pedals 46, and a gear ring 48 for engaging the drive chain 50. Therear triangle 52 of the bicycle frame 22 is shown in FIG. 1 as includinga pair of seat stays 54 (only one shown in FIG. 1) and a pair of chainstays 56 (only one shown in FIG. 1). The seat stays 54 are attached tothe top end of the seat tube 28. The chain stays 56 are attached to thebottom end of the seat tube 28 at or near the bottom bracket 40.

The rear ends of the seat stays 54 and chain stays 56 may be adapted tobe a unitary structure, such as that shown in FIG. 2, or may be anon-unitary structure such as that shown in FIG. 3. These twoalternatives are described in more detail below. Whether unitary or not,the rear ends of the seat stays and chain stays may support a wheel,hub, gear cassette (for engaging the drive chain), disc brake mechanism,and derailleur.

There are many different types of frame structures available for abicycle that are able to adapt the invention herein. For instance, whilea “hard tail” bicycle suspension is shown in FIG. 1, a frame having arear suspension or a full suspension may also be applicable. Each ofthese different frame suspensions support an axle, wheel and hub with achain stay and seat stay structure, where this invention would beimplemented.

Further, the mechanism for attaching the seat stays and chain stays tothe frame is not limiting to the implementation of this invention. Theinvention may also be implemented on the front fork of a bicycle, andmay be implemented on rear triangle structures having one or two seatstays and only one chain stay. This invention may also be utilized on amotorcycle where only a one-sided swing arm is used.

FIG. 2 shows the rear ends of the seat stays 54 and chain stays 56 as aunitary structure. The traditional “drop-out” structure, which receivesthe axle and the hub and typically has a downwardly facing slot to allowthe axle and hub to be removed, is in this example replaced by a axlesupport collar 58. Each of the rear ends of the unitary structureincludes an axle support collar. The axle support collar 58 forms anaperture 60 for receiving a bearing for rotatably supporting the axleand hub structure, as is described in more detail below. The axlesupport collar 58 shown here completely surrounds the aperture 60,however, it is contemplated that the axle support collar 58 may onlypartially encompass the aperture 60 and still adequately receive thebearing to rotatably support the axle and hub structure. Further, theaxle support collar 58 may be positioned other than at the intersectionof the chain stay 56 and seat stay 54 on each side.

FIG. 3 shows a rear triangle where the chain stay 56 and seat stays 54are not a unitary structure, such as that shown in FIG. 2. Each rear endof the chain stay 56 (on each side) is not connected with thecorresponding rear end of the seat stay 54. This type of structure isutilized on some frames that have a rear suspension. In this example,each seat stay 54 end includes an axle support collar 62 having anaperture 64 formed therein, and each chain stay end includes an axlesupport collar 66 having an aperture 68 formed therein. As noted above,the collars 62, 66 may or may not fully surround the aperture 64, 68.The axle support collars 62, 66 receive a bearing (shown below) forrotatable support of an axle and hub received therein. Each collar 62,66 may receive a bearing, or each adjacent pair of axle support collars(i.e. each pair of the seat stay and chain stay on either side) mayreceive a single bearing having a common inner race and a separate outerrace for each stay. This is described in more detail below.

FIG. 4 shows an example of the instant invention implemented in abicycle frame, such as shown in FIG. 1, having a unitary rear trianglestructure. The left and right (as portrayed herein) unitary seat andchain stays each have an axle support collar 58, each axle supportcollar defining an aperture 60. A bearing 70 is firmly seated in eachaperture 60, and each bearing includes an outer race 72 and an innerrace 74, with a plurality of ball bearings 76 positioned between, as isknown. In its seated position, the outer race 72 of each bearing 70engages a shoulder 78 formed on the axle support collar 58. The shoulder78 engages the inside edge of the outer race 72 to help firmly positionthe bearing 70 in place. Each bearing 70, in this example, is a one-waybearing. This allows the chain drive 80 (see FIG. 1) to engage the gearcassette 82 and propel the bicycle when the user pedals in the forwarddirection, and for the hub 84 and axle 86 to free-wheel (rotate freely)then the user holds the pedals still or pedals relatively backwards.

An axle 86 is received through the inner race 74 on each side andextends between the bearings 70. Each end 88 of the axle extends beyondthe bearing 70 on each side. Each axle end 88 has external threading forreceiving a fastener, such as a washer 90 and nut 92, to fasten the axle86 between the axle support collars 58. In this example, the washer 90used on each end 88 of the axle 86 engages the outside edge of thebearing's inner race 74 to apply a compressive load thereto. Thefastener on at least one end may be removable to allow the axle to bepulled out of the bearings. Any suitable fastener is contemplated, suchas a snap ring, friction engagement, or a quick-connect. Where the axlecollar 58 does not fully surround the aperture 60, and forms a slot, itmay be sufficient for the fasteners to simply loosen and allow the axleto be removed through the slot. In this type of structure, the bearing70 may need to be removed from the axle support collar 58 also.

Remaining with FIG. 4, the axle 86 is received in a hub 84, which ispositioned between each of the axle support collars 58. The hub 84snugly fits on the axle 86. Each end 94 of the hub 84 engages the insideedge of each inner race 74 to provide a surface against which thefasteners hold the bearings 70. Either end of the hub may engage anintermediate structure or structures, such as a spacer(s), which in turnengages an inside edge of the inner race 74. The hub 84 may include abrake disc rotor 96 for engagement with the caliper 98 (mounted on theseat stay or chain stay), a gear cassette 82 forming part of the drivetrain 80, and anchors 100 for the spokes 102. Of course the spokes 102extend outwardly from the hub 84 to support a rim and tire, as is known.All together the hub 84 and its components form the wheel 34.

In the structure shown in FIG. 4, the axle 86 rotates relative to theframe 22 as the wheel 34 turns. The hub 84 rotates along with the axle86. The hub 84 may be allowed to rotate relative to the axle 86 if asuitable bearing structure is positioned between the axle 86 and the hub84, such as inside the internal hub channel 104 at either end. Also, thegear cassette 82 may be integral with the hub 84, or may be press-fit onthe hub.

The gear cassette 82 may be mounted on the hub 84 with one or moreone-way bearings. This would allow regular two-way bearings to be usedin the axle support collars 58. Where one or more than one one-waybearing is positioned between hub 84 and the gear cassette 82, the drivechain 50 would drive the gear cassette 82 and the wheel 34 in theforward direction, and would allow free-wheeling when the user held thepedals in one position or pedaled relatively backwards.

To remove the wheel 34 from the frame 22 for replacement, maintenance,or transport, the fastener 92 may be removed from one end 88 of the axle86. The axle 86 may then be pulled axially out of the hub 84 and theaxle support collars 58. The hub 84 and wheel 34 may then “drop out”from between the axle support collars 58. The brake structure and thederailleur and chain may also need to be removed. Installation of thewheel is accomplished by positioning the hub 84 between the axle supportcollars 58 and in aligning the passageway 104 within the apertures 60.The axle 86 is then inserted from one end of the passageway 104 to theother, and the end fasteners 92 applied and tightened.

The structure described herein moves the bearings 70 laterally outwardlyfrom inside the hub 84 to outside the hub 84. The advantages mayinclude: allowing a larger diameter axle for a stronger structure and astiffer assembly, a lighter assembly depending on the dimension andmaterials used, easier access and maintenance of the axle bearings, moredesign flexibility for wheel manufacturers, and more size options forthe axle bearings.

FIG. 5 shows an example of the instant invention implemented in abicycle frame, such as shown in FIG. 1, having a non-unitary reartriangle structure, such as that shown in FIG. 3. The left and right (asportrayed herein) non-unitary seat 54 and chain 56 stays each have anaxle support collar (62, 66, respectively), each axle support collardefining an aperture (64, 68, respectively). A bearing having a commoninner race 108 and separate outer races 110, 112 (and associated ballbearing members 114) is firmly seated in the commonly aligned apertures64, 68 of the left and right paired chain 66 and seat 62 stay axlesupport structures. Focusing on the structure encircled by a dashed line116 in FIG. 5 for explanation, it can be seen that the common inner race108 is received over the axle structure 118 (described in more detailbelow). The inwardly of the two outer races 110 is firmly seated in theaperture 64 formed in the axle support structure 62 of the seat stay 54,and engages an inner shoulder 120 to help properly position the inwardlyof the two outer races 110. The outwardly of the two outer races 112 isfirmly seated in the aperture 68 formed in the axle support collar 66 ofthe chain stay 56, and engages an outer shoulder 122 to help propertyposition the outer races 112. A spacer (not shown) may be positionedbetween the outer races 110, 112 to keep them, and their respective ballbearings 114, separated, or the structure of the outer races 110, 112may be such that they are maintained in a spaced apart orientation evenunder lateral compressive forces.

Remaining with FIG. 5, the axle structure 118 in this example includes acombined axle 124, hub 126, and axle extensions 128. The combined axle124 and hub 126 (collectively 118), similar to that as described abovewith respect to FIG. 4, may include a disc brake rotor 130, spokeanchors 132, and a gear cassette 134. Here, the axle 124 is integrallyformed with the hub 126. Each end 136 of the hub 126 includes threadedrecesses 138 for receipt of an axle extension 128. Each axle extension128 may be both a retaining fastener and bearing surface. Each such axleextension 128 includes a threaded inner end 142 for thread engagementwith the threaded recess 138. The outer portion 144 of the axleextension 128 has an outer circumferential profile sufficient to be abearing surface received in the inner race 108 of the respective bearing106. And the outer end 146 of each axle extension 128 has an engagementportion 146 (such as a knurled grip as shown, or nut, or alien head) foruse in aiding the axle extension 128 to be threaded into the hub 126.

When assembled together, the axle extension 128 is inserted through theinner race 108 of the bearing 106 positioned in the axle support collars62, 66 on one side. The threaded inner end 142 of the axle extension 128is then inserted into the threaded recess 138 of the hub 126, which ispositioned between the left and right ends of the rear triangle to allowalignment of the threaded recess 138 with the apertures 64, 68 formed inthe left and right axle support collars 62, 66. The axle extension 128is then threadedly received in the threaded recess 138 to cause theouter engagement portion 146 to engage (as shown here, the engagement isthrough a washer 148) the outside edge of the inner race 108 and createa laterally compressive force. A shoulder 150 formed at the end of theintegral hub and axle 118, extending radially from the opening of thethreaded recess 138, engages (itself or through another structure, suchas a washer) the inside edge of the inner race 108 to help firmly seatthe bearing 106, and to provide a surface against which the retainingfastener 146 creates the laterally compressive force. This samestructure is found on both sides of the hub 126.

The wheel 34 is removed from the rear triangle for maintenance,replacement or transport by removing both retaining fasteners 146, inthis example by unthreading them from the threaded recesses 138 andpulling the axle extensions 128 substantially out from the common innerrace 108 on each side, and then removing the hub 126 from between theleft and right paired axle support collars 62, 66.

This example of an implementation of the invention also may have thebenefits described above with respect to the embodiment shown in FIG. 4.Additionally, this structure allows the separate seat and chain staystructures on either side of the hub to rotate independently from oneanother.

Each bearing 106, in this example, is a one-way bearing. Similar to thatdescribed above relating to FIG. 4, this allows the chain drive toengage the gear cassette 134 and propel the bicycle when the user pedalsin the forward direction, and for the integral hub and axle 118 tofree-wheel (rotate freely) then the user holds the pedals still orpedals relatively backwards.

It is contemplated that the integral axle and hub 118 may have a recessformed through the center from end to end, with the outer ends of therecesses having the threaded structures to receive the axle extensions128.

Where the axle collars do not fully surround the aperture, and form aslot, it may be sufficient for the retaining fasteners to be simplyloosened and allow the axle to be removed through the slot. In this typeof structure, the bearing 106 may need to be removed from the axlesupport collars also. Further, in this embodiment as with that describedin FIG. 4, the gear cassette 134 may be operably engaged with the hub118 by one or more one-way bearing, thus allowing the other bearings tobe two-way bearings.

The axle 86, mount 92, and hub 84 structure shown in FIG. 4 may be usedin the example shown in FIG. 5 for a non-unitary rear triangle structurewith separate chain stays and seat stays on either side. Likewise, thecombination axle and hub 118 and axle extensions 128 shown in FIG. 5 maybe used in the example shown in FIG. 4.

FIG. 6. shows an alternative angular contact bearing that may replacethe bearing structures used in either FIG. 4 or FIG. 5. This angularcontact bearing would work to replace the individual bearings used inFIG. 4, or it would work in FIG. 5 where each separate seat stay andchain stay has its own bearing. FIG. 6 represents the top of a singlebearing, such as that shown in FIG. 4 and circled by dashed line 151.The attachment structure for the hub and axle in FIG. 6 is similar tothat shown in FIG. 4. The combination axle and hub 118 and axleextensions 128 are used in this embodiment to attach to the axle supportcollar 58 of the unitary rear triangle of the example shown in FIG. 2.The angular contact bearing 152 is positioned in the aperture 60 torotatably support the combination axle and hub 118 and axle extensions128.

In this example of the bearing structure 152, the laterally inner andouter races 154, 156 are separate, and have oppositely sloped radiallyinner 158 and outer 160 races, which when used together may providehigher performance in a axial thrust environment. The outer races 160are contained in a housing 162 with an inner shoulder 164 to engage theinside edge of the inner-most 154 outer 160 race. A retainer 166 on theaxle support collar 58 engages the outside surface of the outer-most 156outer 160 race. The inner-most 154 inner 158 race is contained on itsinside surface by the hub 118, and the outside 156 inner 158 race iscontained by the end of the axle extension/retaining fastener 128. Thisbearing 152 may be a one-way bearing, or a two way bearing in thealternative, as described with respect to FIG. 5. Also, the bearings mayhave seal caps applied to help keep dirt, water, and other penetrablesout of the ball bearing structures. The bearings shown herein areschematic in nature for the purpose of explanation, and may have housingfeatures that act as seals or covers. A suitable angular contact bearingfor these purposes may include product number 432043 by the NationalBearing Co. Further, it is contemplated that the bearings may be otherthan ball bearings, such as roller bearings, and may be replaced withbushings or the like in some circumstances.

The positioning of the axle bearing structures, as described herein,outside of the hub allow a wider engagement position for stronger andmore stiff structure. It also may allow for larger diameter axles andhubs for stronger structures; and may also allow for lighter structureswhere the larger diameters allow for thinner material thicknesses.

Although preferred embodiments of this invention have been describedabove with a certain degree of particularity, those skilled in the artcould make numerous alterations to the disclosed embodiments withoutdeparting from the spirit or scope of this invention as described in thespecification, drawings and claims. All directional references (e.g.,upper, lower, upward, downward, left, right, leftward, rightward, top,bottom, above, below, vertical, horizontal, clockwise, andcounterclockwise) are only used for identification purposes to aid thereader's understanding of the present invention, and do not createlimitations, particularly as to the position, orientation, or use of theinvention. Joinder references (e.g., attached, coupled, connected, andthe like) are to be construed broadly and may include intermediatemembers between a connection of elements and relative movement betweenelements. As such, such joinder references do not necessarily infer thattwo elements are directly connected and in fixed relation to each other.It is intended that all matter contained in the above description orshown in the accompanying drawings shall be interpreted as illustrativeonly and not limiting. Changes in detail or structure may be madewithout departing from the spirit of the invention as defined in theappended claims.

The invention claimed is:
 1. A rear bicycle frame structure forattaching a rear wheel to the rear frame, the rear bicycle framestructure comprising: a seat stay having a first axle support collardefining a first opening; a chain stay having a second axle supportcollar defining a second opening; a first two-way bearing memberreceived within the opening of the first axle support collar; a secondtwo-way bearing member received within the opening of the second axlesupport collar; an axle structure, including a hub having a centralregion for supporting the rear wheel, and defining a first end portionreceived within the first bearing member and the second bearing member,the first and second bearing members being adjacent one another andallowing the first and second axle support collars to move relative toone another; a gear cassette mounted on the hub by at least one one-waybearing and positioned between the central region of the hub and theadjacent first and second bearing members; and wherein the axlestructure rotates relative to the seat stay and the chain stay.
 2. Arear bicycle frame structure as defined in claim 1, wherein the rearbicycle frame is a part of a bicycle rear suspension.
 3. A rear bicycleframe structure as defined in claim 1, wherein the opening defined ineither one of or both of the first or second axle support collar is anaperture.
 4. A rear bicycle frame structure as defined in claim 1,wherein the opening defined in either one of or both of the first orsecond axle support collar is a slot.
 5. A rear bicycle frame structureas defined in claim 1, wherein the first end portion of the axlestructure includes a member received in a cavity formed in the first endportion of the hub.
 6. A rear bicycle frame structure as defined inclaim 5, wherein the member is a bolt threadedly received within thecavity.
 7. A rear bicycle frame structure as defined in claim 6, whereinthe cavity may extend entirely through a length of the hub.
 8. A rearbicycle frame structure as defined in claim 1, wherein the first endportion of the axle structure is integrally formed with the hub.
 9. Arear bicycle frame structure as defined in claim 8, wherein a fasteneris received on the first end of the axle structure.
 10. A rear bicycleframe structure as defined in claim 9, wherein the first end of the axlestructure defines external threads; and the fastener is a nut receivedon the external threads.